Hope the replication has been setup and running. We no need to bother about
the which relay log the slave is reading. It depends on how much lag behind
the current position of the read_master and exec_master.
Thanks
Suresh Kuna
MySQL DBA
2010/1/27 Miguel Araújo <noradone@stripped>
> Suresh - Yes, I know that fact. That's why I will use virtual machines to
> do the tests and analyze the results.
> I hope you can help me with the binary logs doubt.
> Thanks.
>
> Regards,
> Miguel Araújo
>
> On Jan 27, 2010, at 3:03 PM, Suresh Kuna wrote:
>
> Miguel - It varies from machine to machine, network to network, depends on
> several factors like load, the sql you tested and more over all hardware
> components present in the server.
>
> Thanks
> Suresh Kuna
> MySQL DBA
>
> 2010/1/27 Miguel Araújo <noradone@stripped>
>
>> I want to do do a tpcc benchark on a replicated database with a relatively
>> large number of replicas.
>>
>> The major timing issue is right what you've said "when an event will get
>> *executed* on the slave", but I don't want to measure the occasional
>> multisecond delay. As you said, replication is generally fast (in order of
>> milliseconds), and my intention is to measure this delay in the order of
>> milliseconds.
>>
>> So, my approach is to read (each 10ms) the binary logs on master and each
>> slave as the benchmark runs, and compare the position to finally calculate
>> the delay time. And, like I've started questioning in this thread, my doubt
>> is on what relay log to read.
>>
>> Thanks.
>>
>> Regards,
>> Miguel Araújo.
>>
>> On Jan 27, 2010, at 2:35 PM, Johan De Meersman wrote:
>>
>> > The event *arrives* pretty soon after - unless you have a flaky network,
>> that's not really you should worry about.
>> >
>> > The major timing issue will be when an event will get *executed* on the
>> slave, and the answer is: it varies. Events get executed sequentially on the
>> slave, so although it will generally be fast (order of milliseconds), a huge
>> update or other long-running query will block the queue until it finishes,
>> and thus you could see the occasional multisecond delay.
>> >
>> > It all depends on your workload, though.
>> >
>> > 2010/1/27 Miguel Araújo <noradone@stripped>
>> > Hello.
>> >
>> > I want to measure replication speed for a great number of replicas. By
>> that I mean how soon an event arrives at the slave after being logger to the
>> master's binary log.
>> >
>> > So, I've started developing an application to read the replication logs
>> in order to compare them (compare by time, the log position on the master
>> node with the log position on the slave's). My first approach was to use the
>> mysqlbinlog to get the log position, in the 'Master_Log_File'. But in the
>> slave's the last position that the SQL thread has read and executed is the
>> 'Relay_Log_Pos', right?
>> > I have to read the slave's relay log, in order to get the last position
>> on the Master's log executed? And compare with the master's log?
>> >
>> > Thank you.
>> >
>> > Regards,
>> > Miguel Araújo
>> >
>> >
>> >
>> > --
>> > MySQL Replication Mailing List
>> > For list archives: http://lists.mysql.com/replication>> > To unsubscribe:
>> http://lists.mysql.com/replication?unsub=1>> >
>> >
>> >
>> >
>> > --
>> > Bier met grenadyn
>> > Is als mosterd by den wyn
>> > Sy die't drinkt, is eene kwezel
>> > Hy die't drinkt, is ras een ezel
>>
>>
>
>
> --
> Thanks
> Suresh Kuna
> MySQL DBA
>
>
>
--
Thanks
Suresh Kuna
MySQL DBA

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